Aerial device



J. A BINNIE AERIAL DEVICE May 31, 1932.

Filed March 27, 1931 IINVENTOR JOHN A. B/NN/E 0g 2 ATTORNEYS PatentedMay 31, 1932 s'ra'rss PATENT Fries JOHN A. BINNIE, OF PHILADELPHIA,PENNSYLVANIA AERIAL DEVICE Application filed March 27, 1931 Serial No.525,649.

In its preferred form, as described in detail below, the device forms ahollow body of flexible material open at one end and having nostiffening orbracing structure except at such open end, yet such devicewill assume and keep its fully distended active or operative conditionat relatively low speeds (say, five miles per hour) as well at the greatspeeds of which airplanes are capable, one of the intended uses of myinvention contemplating the towing of the device by an airplane, eitherfor target practice, or for the aerial display of advertisements paintedon the outside of the device. Notwithstanding the absence of anyinternal bracing, this improved device is of such strength as towithstand without tearing or bursting, the great strains to which it issubjected at high speeds. 7

Reference is to be had to the accompanying drawings which illustrate asatisfactory and preferred embodiment of my invention, Fig. 1 showingthe same in side elevation, with parts in section, and Fig. 2 in frontelevation, looking from the open endof the device.

The device shown in the drawings is an elongated, substantiallycigar-shaped bag of circular cross section made of suitable flexiblematerial such as muslin. This bag may be made of a plurality of stripsof gores (for instance, six connected by longitudinal seams, asindicated at'a). At the wider end, the bag or body is open, the size andshape of the opening being maintained by a metal ring 10 secured to thefabric of the bag by sewing or in an other suitable manner. Except forsaid opening, the bag is closed, and consists of a frusto-conicalportion 11, flaring away from the open end, and the closed end portion12, which in longitudinal section is substantiallyof paraboliccurvature. For the purpose of connecting the bag with the towingairplane, I provide grommets 13 on the fabric adjacentto the ring 10, atequal distances from each other, and through said grominets'and aroundthe ring 10 I loop one end of a set of lines 14, their other ends beingattached to a swivel ring 15, to which the tow-line 16 of theairplane isconnected.

It will be understood that except for the metal ring 10, the bag has nobracing or stiffening members, and is perfectly flexible. hen air rushesinto the open end of the bag, as it will when the bag is towed behind anairplane, it will distend and, as it were, in-

flate the bag so as to keep it substantially rigid and maintain it inthe shape illustrated by Fig. 1. The bag will therefore present anunvarying appearance, which is of importance when it is to be used as atarget, or as a background or carrier for an advertisement painted onits outer surface.

In the practical use of devices of the character described, considerabledifficulty was experienced at first on account of the special qualitiesrequired of the bag or envelope to enable it to perform equally well athigh and at low speeds. When the envelope is of relatively greatporosity, the bag will remain limp at low speeds, and fail to assume itsoperative, distended shape. If, however, the envelope has but littleporosity, or practically none (for instance, when made of rubber), itwill rip or burst at high speeds. The degree of porosity must be such asto permit a sufficient amount of air to pass outwardly through thefabric of the envelope at high speed, to prevent bursting of the bag,yet the air must not pass through the fabric too freely, since then thedevice will not operate properly at low speeds. I have found that theproper degree of porosity can be obtained, in the case of muslin orsimilar fabrics, by applying on the outside of the bag, a single,relatively thin coating of a suitable porosity-reducing substance. Ihave used a coat of pantasote for this purpose, and found it highlysatisfactory.

The particular shape of the bag facilitates its proper operation and bystream line formation reduces skin friction. The application of theorosity-reducing substance on the outside 0? the envelope gives it asmoother surface than it would have otherwise and increases thedurability of the device.

7 6 Various modifications may be made without departing from the natureof my invention as set forth in the appended claims.

I claim: 1. A device of the class described, com 10 prising an elongatedbag open at one end and made of a porous fabric the pores of which arepartly filled with a porosity-reducing substance, so as still to permitthe passage of a certain amount of air through said fabric. 16 2. Adevice of the class described, comprising an elongated ba open at oneend and made of a porous fa ric having an exterior coating of asubstance which will reduce the porosity of said fabric while still 20permitting the passage of a certain amount of air therethrough.

In testimony whereof I have hereunto set i my hand.

JOHN A. BINNIE.

